Stochastic bivariate time series models of waves in the North Sea and their application in simulation-based design

In this paper, we present and evaluate three long-term wave models for application in simulation-based design of ships and marine structures. Designers and researchers often rely on historical weather data as a source for ocean area characteristics based on hindcast datasets or in-situ measurements. The limited access and size of historical datasets reduces repeatability of simulations and analyses, making it difficult to assess the sampling variability of performance and loads on marine vessels and structures. Markov, VAR and VARMA wave models, producing independent long-term time series of significant wave height (H_s) and spectral peak period (T_p), is presented as possible solutions to this problem. The models are tested and compared by addressing how the models affect interpretation of design concepts and the ability to replicate statistical and physical characteristics of the wave process. Our results show that the VAR and VARMA models perform sufficiently in describing design performance, but does not capture the physical process fully. The Markov model is found to perform worst of the tested models in the applied tests, especially for measures covering several consecutive sea states.     

耐压柱壳参数化设计与灵敏度分析

为提高耐压柱壳设计效率,设计了耐压柱壳参数化分析流程。研究了有限元分析所涉及的材料属性、载荷施加、边界条件设置等内容,确定了采用弧长法分析耐压柱壳稳定性。利用Python语言对于ABAQUS软件进行了二次开发,利用Isight软件实现了ABAQUS的集成,实现了耐压柱壳有限元分析模型的网格自动划分、自动分析计算等。选择样本点进行参数化分析,利用响应面模型对于样本点进行了拟合,得到了具有较高拟合精度、满足工程需要的近似模型,进行了设计变量的灵敏度分析。研究结果表明:参数化分析流程可实现耐压柱壳的自动分析、近似模型及灵敏度分析,可降低耐压柱壳分析难度,均可提高耐压柱壳设计效率。     

兼顾志愿者地理信息的国家应急测绘公众服务平台设计

随着互联网技术的进步和新一代网络信息传播模式的深入发展,志愿者地理信息的研究和应用日益广泛,但由于其规范性和均一性方面的缺陷,在应急公共服务领域,志愿者信息的有效利用依旧是亟需突破的难题。本文将重点介绍国家应急测绘公众服务平台设计思路和总体架构,并结合志愿者地理信息特点,探讨该类信息在国家应急测绘公众服务平台建设中的处理流程和应用模式,力求在应急信息资源共享和服务平台共建方面进行新的尝试,为我国突发事件应急体系建设提供有益实践。     

A literature synthesis of LiDAR applications in transportation: feature extraction and geometric assessments of highways

Interest in using Light Detection and Ranging (LiDAR) technology in Transportation Engineering has grown over the past decade. The high accuracy of LiDAR datasets and the efficiency by which they can be collected has led many transportation agencies to consider mobile LiDAR as an alternative to conventional tools when surveying roadway infrastructure. Nonetheless, extracting semantic information from LiDAR datasets can be extremely challenging. Although extracting roadway features from LiDAR has been considered in previous research, the extraction of some features has received more attention than others. In fact, for some roadway design elements, attempts to extract those elements from LiDAR have been extremely scarce. To document the research that has been done in this area, this paper conducts a thorough review of existing studies while also highlighting areas where more research is required. Unlike previous research, this paper includes a thorough review of the previous attempts at data extraction from LiDAR while summarizing the detailed steps of the extraction procedure proposed in each study. Moreover, the paper also identifies common tools and techniques used to extract information from LiDAR for transportation applications. The paper also highlights common limitations in existing algorithms that could be improved in future research. This paper represents a valuable resource for researchers and practitioners interested in knowing the current state of research on the applications of LiDAR in the field of Transportation Engineering while also understanding the opportunities and challenges that lie ahead.     

Inpho交互式方位角定义在ADS影像生产中的应用与研究

目前,Inpho全数字摄影测量系统针对航空三线阵影像具有较为成熟的处理流程。但是随着摄区环境和飞行成本要求的不断提高,航线方向不再局限于坐标轴方向,斜飞模式逐渐增多。本文在Inpho系统DOM影像制作原理的基础上,对比研究交互式方位角定义在ADS影像生产中的普遍适用性,进一步优化Inpho系统针对ADS数据的解决方案。     

地理国情普查数据预处理软件主体功能设计

为满足地理国情普查数据库建设技术设计要求,全国各省市普查数据成果都需要进行全面的入库前预处理。处理过程烦琐,若采用人工方式,工作效率低下且数据质量难以保证。本文依托丰富的实际生产经验,在进一步筛选和不断总结的基础上,对地理国情普查数据预处理软件进行了主体功能设计。     

Cartographic Design and the Space–Time Cube

This paper reports on the results of an empirical evaluation that aimed to define the effectiveness and efficiency of different visual variables in depicting the Space–Time Cube’s (STC) content. Existing STC applications demonstrate that the most used visual variables are size and colour hue. Less is known, however, about their usability metrics. The research sets design criteria for STC contents, such as space–time paths, based on the cartographic design theory. The visual variables colour hue, colour value, colour saturation, size and orientation have been applied in two different use case studies. Besides, to support the three-dimensional visual environment, depth cues such as shading and transparency were considered too. User tests have been executed based on real-world problems with particular attention for the visualization strategy and data complexity. The outcomes revealed the most efficient and effective visual variables to represent data of various complexities in the STC.     

Cartographic Symbol Design Considerations for the Space–Time Cube

The cartographic representation of geographic phenomena in the space–time cube comes with special challenges and opportunities when compared with two-dimensional maps. While the added dimension allows the display of attributes that vary with time, it is difficult to display rapidly varying temporal data given the limited display height. In this study, we adapt 2D cyclic point symbols to construct 3D surfaces designed along a helical path for the space–time cube. We demonstrate how these complex?3D helical surfaces can display detailed data, including data reported daily over 100 years and data reported in four-hour intervals over a year. To create the point symbols, each value is plotted along the curve of a helix, with each turn of the helix representing one year or week, respectively. The model is modified by varying the radii from the time axis to all points using the attribute value, in these cases maximum daily temperature and four-hourly ridership, and then creating a triangulated surface from the resulting points. Using techniques common to terrain representation, we apply hue and saturation to the surface based on attribute values, and lightness based on relief shading. Multiple surfaces can be displayed in a space–time cube with a consistent time interval facing the viewer, and the surfaces or viewer perspective can be rotated to display synchronized variations. We see this method as one example of how cartographic design can refine or enhance operations in the space–time cube.     

地图审核在线审批系统分析与设计

随着互联网技术的发展和“互联网＋”业态的兴起,电子政务成为推进审批服务便民化的重要内容。地图审核作为一项行政许可,主要分为申请和受理、技术审查、审批和送达及样本备案4个业务环节。根据上述业务步骤,本文对地图审核在线审批系统的设计进行了分析,完成了系统的构建与应用,为同类型其他系统的构建提供了参考。     

关于地图人性化设计的思考

首先分析了地图人性化设计的目的;接着从地图使用功能、表现形式、语义符号和内容编排等方面阐述了地图人性化设计的内涵;最后提出了人性化设计的原则,旨在使地图作品越来越满足人们现代生活的需求。